Brick Wall Filter

A brick wall filter is a low or high-pass filter (LPF or HPF) that completely cuts off audio signals above or below a pre-selected frequency. For example, putting brick wall filters at 60Hz and 10kHz will cut off any audio below 60Hz and above 10kHz, but will leave all other frequencies completely intact.

Brick wall filters suddenly and completely remove all audio beginning at the frequency selected, as opposed to traditional low and high pass filters, which have a slope, or graduated decrease in level beginning at the selected frequency.